The most prevalent problem when upgrading to iOS 5 is "Error 3200." Apple's service reps are telling multiple users that this error is something they're working on, and add that there is nothing users can do to change that error code.
The problem is occurring because there are too many people trying to access Apple's servers at the same time. The reps say the problems should subside in a few hours.
The problem starts when your device tries to contact Apple servers for authorization. When the servers were slammed the hardest, many of the requests were not being fulfilled. As a result, many users are reporting trying over again, where the Error 3200 mysteriously disappears.
So one way to solve the problem is just to keep trying. Since Apple's servers are said to only be fulfilling about half the requests, you can easily win the coin-flip and get authorization.
Other problems reported:
Having to reorganize all your apps.
Backup taking a long time. One user told us it took three hours.
Downloading the upgrade taking a long time. It's more than 700 MB, and because the servers are so overburdened, it's taking longer than usual.
Inability to register for iCloud.
On the positive side, a few users are saying the process has been seamless -- even though most find it takes a long time to download iOS 5. Some report downloading the update in 15 minutes. But after that, there is an extra backup process that takes much longer than usual.
If all this is too much for you, just wait couple of hours. Meanwhile, check out our iOS 5 gallery, below.